How Did RAMAC Work?

How Did RAMAC Work?

Storing data on magnetic tapes and drums was well established by 1957. IBM’s RAMAC team adapted the principle of magnetic storage to a spinning disk. Or rather, 50 spinning disks, each two feet across.

A moveable arm held two magnetic heads that read and wrote data—one head for the underside of disks above the arm, one for the tops of disks below the arm. Continuous airflow from a compressor prevented the heads from touching the disks.

It took, on average, only 0.6 seconds to retrieve a piece of data from anywhere on RAMAC.

This shows the “spin-coating” technique IBM used at the early experimental stage to apply a magnetic surface to metal disks for RAMAC. More advanced and automated coating techniques were used once RAMAC was in production.